Module:Discussion ping

--- This module extracts all the users in either a marked LST or in wikitext and
-- generates links reflecting a courtesy ping.
-- 
-- @module discussion_ping
-- @require Module:Arguments
-- @release alpha

local p = {}
local getArgs = require("Module:Arguments").getArgs

--- Makes a user link
-- @param {table} userTitle the title for the user object
-- @return {string} the formatted user link in the form of a ping
local function makeUserLink( userTitle )
	return mw.ustring.format( '@[[%s|%s]]', userTitle.prefixedText, userTitle.text )
end

--- Entry point for module
-- @param {table} frame processing frame
-- @return {string} wikitext
function p.main( frame )
	local args = getArgs( frame )
	return p._main( args, frame )
end

--- The main function for this module
--
-- @param {table} args processing arguments
-- @param {string} args.wikitext Wikitext to extract pings from
-- @param {string} args.title Name of title to check for pings
-- @param {string} args.section LST section
-- @return List of pings
function p._main( args, frame )
	frame = frame or mw.getCurrentFrame()
	if not mw.isSubsting() and not args['__demo'] then
		error( "Module:Courtesy ping must be substituted", 0 )
	end
	local links = {}
	local noPing = {}
	local i = 1
	while args["noping" .. i] do
		noPing[ args[ "noping" .. i ] ] = true
		i = i + 1	
	end
	local wikitext = args['wikitext'] or args[1] or nil
	local pageToInclude = args['title'] or ''
	local sectionName = args['section'] or nil
	local lstTitle = mw.title.new( pageToInclude )
	if not wikitext and lstTitle then
		if sectionName or ( lstTitle.fragment and lstTitle.fragment ~= '' )  then
			wikitext = frame:callParserFunction('#lsth', { lstTitle.prefixedText, sectionName or lstTitle.fragment })
		else
			wikitext = frame:preprocess(lstTitle:getContent())
		end
	elseif not wikitext then
		error( "Wikitext or a page title with section must be specified!", 0 )
	end
	
	-- Thanks ChatGPT
	for link, display in mw.ustring.gmatch(wikitext, "%[%[([^%[%]|]+)%|?([^%[%]]*)%]%]") do
	    if display == "" then
	        display = link  -- No display text, so use the link itself
	    end
		if not links[ link ] then links[ link ] = mw.title.new( link ) end
	end
	
	local out = {}
	
	for k,v in pairs(links) do
		if v ~= nil then
			if v.namespace == 2 and not v.isSubpage and not noPing[ v.text ] then
				table.insert( out, makeUserLink( v ) )
			end
		end
	end
	
	return '<!-- Begin [[Module:Discussion ping]] -->' .. mw.text.trim( table.concat( out, ' ' ) )
		.. '<!-- End [[Module:Discussion ping]] -->'	
end

return p